Concrete-iron construction



' (No Model.)

E. L. RANSOME. Y GONORETE IRON CONSTRUCTION.

No'.542,206. 4 Patented July Z, 1895.

v #im v l STATES reina.

CONCRETE-IRON CONSTRUCTION.

SPECIFICATION forming part of Letters Patent No. 542,206, dated July 2,1895.

Application filed October 10. 1894:. Serial No. 525,531. (No model.)

To all whom it may concern: 1

Be it known that I, ERNEST LESLIE RAN- SOME, a citizen of the UnitedStates, residing at Chicago, county of Cook, and State of Illinois, haveinvented an Improvement in Concrete-Iron Construction; and I herebydeclare the following to be aclear and exact description thereof.

My invention relates 4to that class of construction in which thestrength of the structure is largely increased by the embedment of ironbars into the body of the material, and it is an improvement upon theconstruction for which Letters Patent No. 305,226, of September 16,1884,' and No. 516,113, of March 6, 189i, were granted me. 4By thoseinventions a continuous bond was created between the cement and the ironby means of long spiral threads formed upon the bar by twisting, squareor polygonal iron being used.

My present invention consists in an alteration to the form of such bars,whereby the longitudinal bond created by the threads is en# larged andthel transverse bond greatly increased.

According to this invention one or more of the sides or planes betweenthe spiral threads or ridges are made concave or recessed, instead ofbeing dat, as heretofore.

The accompanying drawings illustrate this invention.

Figures 1, 2, and 3 represent various crosssections of my improved bar.Figs. 4 and 5 are end views of the ordinary twisted and my improved barsrespectively, embedded in concrete beams D D in the usual manner, eachhaving one-eighth of a circumferential twist in its length. The arrowsindicate the direction of the strain upon the beam when it is loaded.

It is apparent that concaving the sides of the bar intensities thespiral'threads, fins, or webs created on the bar, and that in makingthese more prominent the bond. between the concrete and the iron isincreased. This is an advantage, but the chief advantage of thisinvention is in the greater cross or transverse bond which it makes.l

It will be observed that in Fig. 4, which represents the ordinarytwisted bar, the tendency of the concrete to split or separate, so faras thev bar influences it, is only hindered by the adhesion and slightirregularities of the surface of the iron.

Take, for example, the tendency to split along the line A A. But for theadhesion of the concrete to the iron and the small irregularities of theparallel sides B B there is nothing relative to the bar to prevent theconcrete from breaking along the line A A following the direction ofthethread. By making the sides of the bar concave, as shown in Figs. 1, 2,3, and 5, this tendency to split along the line A A is not only hinderedby the previously-mentioned adhesion and irregularities but it isresisted by the positive obstruction of the outward curve of sides B B',as shown in Fig. 5, to such an extent that before its resistance can beovercome the concrete must shear apart along lines C C. The likeresistance will in like manner be found wherever the line of strain mayoccur, and in narrow beams of concrete-iron'construction such resistanceis of great importance and benefit. It is also of great value where theiron is used for resisting compression, for the more closely andperfectly the concrete and iron can be bonded together in such cases thebetter will they act infunison and the greater will be their poweys ofresistance.

For the purpose of this invention I regard stone, brick, and othermasonry, glass, or like substance as the equivalent of concrete, andother metals having the requisite characteristics as the equivalent ofiron.

yThe recess may be obtained in the commercial irons in the star-shapebars, as shown.

in Fig. 2, or it may be rolled specially as de- Sired.

When used for withstanding compression, the bars may be cast instead ofbeing wroughtiron.

What I claim as new, and desire to secure ERNEST LESLIE RANSOME.

Witnesses:

LILLIAN GRAY, S. FERD. HowE.

